Window guards made of interlocked metal bars are often installed in the bottom of windows in order to prevent small children or pets from falling from the window. Typically, window guards are designed and tested to withstand about 150 pounds of pressure. Window guards are usually recommended for installation in windows located on the second story and above of a building. See U.S. Pat. No. 6,141,912(Graham). Security bars are also know in the art. Such bars deter entry from the outside by burglars. See: U.S. Pat. No. 4,817,324 (Badger); and US Pat Pub. 2009/0277092 (Dochtermann).
Government agencies often recommend the use of operable window guards, in particular, window guards with a release feature which allow them to be released and removed from the inside without the use of separate tools, keys, or excessive force, so as to permit escape in the event of an emergency. When telescoping bars are used, there are often local regulations on the amount the telescoping bars can be extended. There is a concern that the guard provides a strong deterrent to children and pets from falling through the window guard and out the window. For example one locality requires that when a window guard is used with telescoping bars extended to the maximum allowable width, there is a minimum overlap of five (5) inches or ⅓ of the length of the bar, which ever is greater.